1. Field of the Invention
This invention relates broadly to film roll mounting assemblies used in color printers or the like machines, and especially an attachment spool member thereof to be detachably attached to one end of the core sleeve mounting thereon a roll film mass.
2. Prior Art
These core sleeves are mostly manufactured from paper material, especially on account of cost- and weight reduction possibilities. It has been frequently experienced that these conventional core sleeves lack dimensional preciseness which for example causes various troubles in sensing color zone positions on a tricolor film.
An embodiment of related prior art will be illustrated with reference to FIG. 1 of the accompanying drawings, in advance of detailed disclosure of an inventive embodiment, for better understanding of the invention.
In FIG. 1, a standard model of a conventional film reel or more specifically film roll cartridge proper FC is shown in a perspective view.
In FIG. 1, numeral 1 represents a core sleeve, on which a cylindrical film roll 2 consisting of a long film sheet F, only a part of the latter being shown as has been taken out from the roll, for more convenient illustration purpose only.
In service position, the cartridge proper FC is mounted within the housing of a color printer for cooperation with a conventional thermal head.
In service, the film strip or sheet F is drawn out from the film roll successively and the ink on the sheet F is transferred onto a transfer paper, not shown, each time when the thermal head is operated for execution of printing operation, as is conventionally known.
In a color printing operation with use of a transfer type thermal printer set forth above, such a film roll is utilized by having several different color coatings such as cyanic, yellow, magenta successively applied on the film surface. For each of these color coatings, a separately identifying marking, as at M in FIG. 1, is provided on the end edge zone Fe, which is sensed by a sensor mounted within the color-printing machine, for printing cooperation. In the printing service, therefore, any selected color coating zone may be brought into registration with the transfer service section of the machine, relying upon the corresponding color identifying marking M, and in a successive operation order.
For this purpose, the film roll must be selectively and precisely positioned relative to the transfer service section of the machine. If the film roll was incorrectly mounted the sensor would not be able to detect the selected marking at M.
According to a certain related prior proposal, spools are attached onto both ends of the core tube 1 by taking the end extremities 1a; 1b thereof as the respective reference planes, for precise holding of the film roll 2 relative to the machine housing.